Crack from cleric and fool in church (8)
I believe the answer is:
crevasse
'crack' is the definition.
(crevasse is a kind of crack)
'cleric and fool in church' is the wordplay.
'cleric' becomes 'Rev' (abbreviation for Reverend).
'and' says to put letters next to each other.
'fool' becomes 'ass' (both can mean a stupid person).
'in' indicates putting letters inside.
'church' becomes 'ce' (Church of England).
'rev'+'ass'='revass'
'revass' placed within 'ce' is 'CREVASSE'.
'from' is the link.
(Other definitions for crevasse that I've seen before include "cold break" , "climbing hazard in glacier" , "Crack in a mountain slope or a glacier" , "Sever sac (anag)" , "Deep glacial crack" .)